Airlines have little or no choice about airports they operate at and the air traffic control agency they use.
But passengers have a wealth of options when booking flights.
Rapid growth in demand for flights led to 11 new carriers operating at Auckland Airport alone in a two-year period and, while this growth rate has levelled off, competition between airlines is as hot as ever.
In real terms, air fare increases have been running well below the Consumer Price Index for the past decade and continue to run at record lows.
This is why airlines are so wary of